FORT MYERS, Fla. The former owner of a dietary supplement company that sold weight-loss and attention deficit pills containing an illegal stimulant received an 18-month prison sentence in federal court on Monday.

Derek Vest, who has 60 days to surrender to authorities, will also serve a year of supervised release following his sentence.

Vest’s sentence is part of a plea deal that included testifying in other investigations and forfeiting $2.5 million federal officials estimated he made off of Phen Tabz, Add Tabz and Phen Tabz Teen between April 2013 and November 2014.

The supplements, made by Fort Myers-based Gentech Pharmaceutical, contained DMAA, a banned amphetamine derivative that the company didn’t list on product labels.

DMAA is touted as a natural stimulant, but especially when combined with other ingredients such as caffeine, can elevate blood pressure and result in cardiovascular problems ranging from shortness of breath to a heart attack, according to the U.S. Food and Drug Administration.

In 2012, the FDA issued warning letters to companies using DMAA in their products to remove them from the market or recreate their products without it.